1. Field of the Invention
The present invention relates to an image recording device.
2. Description of the Related Art
A printer using the so-called FWA (Full Width Array) ink-jet recording head that covers the width of recording medium is capable of enhancing a printing speed remarkably, compared to the so-called serial ink-jet printer, because it does not scan the print head back and forth. Therefore, the printer is suitable for mass continuous printing. Also the printer is capable of reducing the device size significantly, compared to the so-called laser printer using toner, because the structure of the printer is simple.
A drum-type printer 400 as shown in FIG. 12, for example, completes printing when an ink-jet recording head 404 scans one rotation in the rotating direction of a drum 402 (when the drum 402 makes one rotation with paper P wound thereon); therefore, the printer 400 is capable of high-speed printing, compared to the serial type printer, which does not complete printing until making several reciprocating scans of the ink-jet recording head 404 in the direction perpendicular to the transferring direction of the paper P. The printing speed of the drum-type printer 400 depends on the rotating speed of the drum 402; accordingly, the printing speed is enhanced theoretically as the rotating speed of the drum 402 is increased.
However, the drum-type printer as such involves a time loss while mounting/peeling the paper P on/from the drum, and the actual performance cannot be enhanced in proportion to increasing the rotating speed of the drum.
Increasing the rotating speed of the drum and mounting the paper at a high speed are likely to create dislocations and/or vibrations of the paper retained on the circumference of the drum. If this happens, it will dislocate the point of impact of the ink drops ejected from the ink-jet recording head and adhere the ink drops at dislocated positions on the paper, which will deteriorate the printing quality to a great extent and create a possibility of quality deficiencies.
To deal with this problem, a construction has been proposed which performs to divide a series of operations of mounting, printing, and peeling-off of printing paper by one rotation during the rotation of the drum (refer to, for example, Japanese Published Unexamined Patent Application No. Hei 10-193581 (FIG. 1, pp. 3 to 5)).
The above method performs paper mounting and peeling separately from printing to attain a stable operation, but it takes extra time for that operation. Naturally, the throughput capacity will be deteriorated during continuous printing because the printing is impossible during paper mounting and peeling.
Another construction has been proposed which prepares a high speed and a low speed as the rotating speed of the drum, and controls the rotating speed of the drum to the low speed when mounting the paper on the drum and to the high speed when performing printing on the paper mounted on the drum (refer to, for example, Japanese Published Unexamined Patent Application No. 2002-283629 (FIG. 3, pp. 3 to 4)).
This method only lowers the rotating speed of the drum without stopping the rotation during mounting the paper; therefore, the drum itself is driven without stopping the rotation, however this method does not deal with the lowering of the processing speed.